Fuse-plug



A. F. DAUM.

FUSE PLUG.

APPLICATION FILED NOV. 24 l9l9.

Gum/M4 Patented Feb. 8, 1921.

f/Qf/DdL/J? UNITED STATES PATENT OFFICE.

ALBERT I. DAUM, OF PITTSBURGH, PENNSYLVANIA.

FUSE-PLUG.

Application filed November 24, 1919.

To all whom it may concern Be it known that I, ALBERT F. DAUM, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Fuse- Plugs, of which the following is a specification.

This invention relates to improvements in fuse plugs, pertaining more particularly to plugs of the general type disclosed in my companion application filed September 12, 1914, Serial No. 861,414, viz. plugs in which the fusible element is extended through the closed end of the plug casing and forms a direct contact with a terminal of the socket.

In the companion application, the opposite end terminal of the socket contacts with a ferrule which, in turn, is connected to a rigid connection or bracket which leads into the casing, the fusible element,in strip formbeing connected to the bracket within the casing. While the plug of the'companion application is of a form to decrease the cost of manufacture, by dispensing with the necessity of a special contact at the closed end of the plug, the cost of the ferrule and of the connection or bracket form material items in the cost of manufacture, owing to the character of material required and the particular forms necessary for the purpose.

The present inventionis designed to still further reduce the cost of manufactureand at the same time preserve the feature of ready renewal of fusible elementsby substituting the fusible element itself for the ferrule and. cpnnection or bracket of the earlier structure, both terminals of the socket having direct connection .with the fusible element.

In addition, the cost may be further reduced by substituting a simple and less expensive structure for the removable cap, the plug thus being produced mainly of insulatmg material, such for instance as porcelain, glass, fiber, etc.

To these and other nature of which will be readily understood as the invention is. hereinafter disclosed,

said invention consists in the improved con-- struction and-combination'of parts hereinafter more fully described, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims,

In the accompanying drawings, in which Specification of Letters Patent.

ends, therefore, the

Patented Feb. 8, 1921'.

Serial No. 340,307.

similar reference characters indicate similar parts ineach of the views, 1

Figure 1 is a vertical sectional view take through one form of plug, the latter being seated in a complemental socket, also shown in section.

Fig. 2 is a sectional view showing a modified form of plug.

Fig. 3 is a bottom of Fig. 2.

Fig. 4 is a I view, partly in section and partly in elevation, showing a further modification. F Fig. 5 is a top plan view of the plug of Fig. 6 is a further modification shown in longitudinal section.

Fig. 7 is a still further modification, shown in section. 1

v Fig. 8 is a top plan view of the structur of Fig. 7.

Fig. 9 is a sectional view of another modiplan view of the plug fication.

Fig. 10 is a top plan view of the same.

In the drawings, 15 designates the hollow casing, formed of insulating material, such for instance as porcelain, glass, fiber, etc., the casing havinga closed bottom 15 with a projecting teat or projection 15 on its outer face, said teat forming a seat for one terminal end of the fusible element 16-preferablyin strip form-the closed end having a slot 15 for the passage of theelement in reaching the seat.

The exterior of the casing is preferably of the two-diameter type, the portion of smaller diameter having the usual co'arse threads 15., with the possible exception of a portion 15 forming a depression leading from a lon-' end seated on the face of teat or projection 15 and may, as in the companion application and as shown in Fig. 6, extend into a depression on the closed end; however, I preferably provide an additional slot 15 in the closed bottom spaced from slot 15 the distance of the teat or projection, and through which the free end of the element is led back into the interior of the casing and bent over as shown, for instance, in Fig. 1. This latter arrangement is preferred, since it eliminates any possibility of the end of a blown strip dropping off of the plug when the latter is removed for renewal of the fuse, thus preventing the possibility of a dropped element portion bridging the terminals of the socket. Obviously, either slot 15 or 15 may form the slot through which the free end is passed, the other slot forming the passageway for the strip which leads into the interior.

The element extends through slot 15or slot 15 as the case may bethrough the interior of the casing, over said ledge and then through slot 15 along depression 15 and over on to the threaded portion 15, as in Fig. 1, or into a recess 15 having a recessed offset 15*, as in other figures. In either case, a portion of the fusible element overlies the unbroken threaded portion 15 and hence is in directcontact with the threaded contact 17 of the socket 17, when the plug is screwed or threaded into the socket, the opposite terminal end of the fusible element which overlies the teat or projection 15"-- contacting with the other terminal 17 of the socket.

In each instance, therefore, opposite end portions of the fusible element-both external of the plug casing-are in contact with the separate terminals of the socket, and are so located as to practically prevent the formation of an are between these terminals. This leaves the interior of casing 15 to receive the intermediate portion of the fusible element, and as thelatter may and preferably is formed with a weakened portion in this interior-length of the element, it will be readily understood that blowing of the element. will take place within the interior of the casing, the contacting ends being less likely to blow by reason of the metallic contact with the socket terminals. Obviously, threaded portion 15 is threaded directly to the socket, the usual ferrule being omitted, thus decreasing cost of production in this respect.

Various forms of closure for the casing may be employed, each including the usual micaelement 18 or its equivalent.-

In Fig. 1 I' have shown the usual ferrule 19 threaded to the portion of the casing of larger diameter, the ferrule overlying element 18. This ferrule may also be employed in the form shown in Fig. 2 or where this portion of the casing has a threaded exterior, the structure being such as to retain element 18 in position overlying the bent portion of the fusible element which extends over the ledge.

In Figs. 1 and 5 I have shown the ferrule substituted by a resilient strip 20 bent to form legs 20 which extend through longitudinal openings 15 of the casing, the legs 20 having feet 20 which extend beneath a shoulder exterior of the casing, this strip overyling the mica element, and being readily removed by springing the legs inwardly to bring the feet into alinement with openings 15. In Fig. 6 I show this arrangement applied to a formation in which the ledge is depressed, thus locating the mica element within the casing.

In Figs. 9 and 10 I show a variation of this latter structure, the openings 15 being omitted, the resilient strip being carried over the portion of the casing of larger diameter and having its feet bent inwardly instead of outwardly, the feet passing beneath the shoulder formed at the junction of the two portions of the casing of different diameters. The legs of the strip may pass through external longitudinal grooves, if desired.

Obviously, the tension of the strip of Fig. I will be exerted in directions opposite to that of Fig. 9.

In Figs. 7 and 8 the mica element is held in position by a split washer 21 underlying lugs 15 formed on the casing.

As will be understood, the structures of Figs. 4 to 10 eliminate the necessity for employing the ferrule structure 19, reducing the cost of manufacture accordingly. As a result, the use of metallic formations is reduced to a minimum, the major portion being the hollow casing and the fusible element.

As will be understood, the different views show 5 various formations for illustrative purposes only. These may be arranged in any preferred way, as for instance the closed end arrangement of Fig. 6 may be employed with all forms, the strip of Fig. 10 may be used as shown in connection with the strip of Fig. 6, the outer end terminal may, be as in Figs. 1 or 2, etc.

I hile I have herein shown and described various ways in which my invention may be carried into effect, it will be readily understood that changes and modifications therein may be found desirable or essential in meeting the various requirements of use, and I desire to be understood as reserving the right to make any and all such changes or modifications as may be found desirable or necessary, in so far as the same may fall within the spirit and scope of the invention as expressed in the accompanying claims when broadly construed.

Having thus described my invention, what I claim as new is:

1. .A renewable fuse plug comprising a memos hollow casing of the cup type, said casing having an external seating face for a fusible element positioned to locate predeterminedportions of the element in direct contact with the terminals of a complemental socket and an intermediate portion of the element within the interior of the casing.

2. In a renewable fuse plug, a hollow casing having a closed end and an external seat for an end portion of a fusible element, said casing having a threaded portion adapted to thread into a complemental socket, said casing also having a longitudinal opening and a depression leading to said threaded portion to constitute a portion of the threaded portion as a seat for the opposite end portion of the element to permit direct contact of the element and a socket terminal. 3. A fuse plug of the type of claim '2 char acterized in that the threaded portion of the casing is provided with a recess located beyond the threaded portion and into which the end of the fusible element may extend.

4. A fuse plug of the type of claim 1 characterized in that the hollow casing is provided with a ledge over which the fusible element is led, an insulating element closing the open end of the casin and overlying said ledge and the fusible element, and

element in position.

5. In a fuse plug adapted to engage a socket, a hollow casing having an open end and formed to receive'a fusible element with the latter extending both exteriorly and interiorly of a casing wall, said casing having longitudinal openings extending from the means for removably securing the insulating plane of-said open end, and also having a shoulder positioned to be exposed when the plug is seated within its socket, an insulatm element for closing said open end, an

means for removably securingsaid insulating element in position, said means comprising a strip-like member overlying said inlying position.

sulatin adapte to traverse said openings and removably on age such shoulder.

6. In a use plug adapted .to engage 'a socket, a hollow casing having an open end and. formed to receive a fusible element with the latter extending both exteriorly and interiorly of a casing wall, said casing having a shoulder positioned to be exposed when the plug is seated within itssocket, an insulatmg element for closing said open end, and

- element with the terminals, said casing having a formation to permit an intermediate portion of the element to traverse the interior of the casing; v p

8.v A plug fuse comprising a hollow casing having a closed end and-formed to provide independent external seats in opposition to the terminals vof a complemental socket, and a fusible element having a length to traverse the interior of the casing and extend in overlying relation to said seats, said closed end of the casing being formed to permit the element to pass therethrough into seating position and reenter the casing interior to permit the element end to be supported against dropping in the presence of a blown elemen p 9. A fuse plug of the type of claim 8 characterized in that the casing is provided with a recess beyond another seat to anchor the oppositeend of the element in its seat over- ALBERT mum.-

element and having portions 

